The invention relates to a tuner with a radio-frequency pre-stage whose output is connected to an input of a mixer stage. An oscillator signal from an oscillator is additionally fed to the mixer. The mixer is formed by a transistor which incorporates an emitter resistor in its emitter circuit and a collector circuit from which the intermediate-frequency signal is taken. Tuners of this kind are familiar from commercially available radio sets, particularly those equipped for reception in the FM band. A requirement which such tuners have to meet is that they must also be capable of handling without distortion fairly large input signals which result from, for example, cross-modulation or mixing products of harmonics. It has been proposed to connect in the path of the radio-frequency signal a variable voltage divider, consisting of diodes whose impedance is altered by a control circuit in the manner indicated in, for example, DE-OS No. 28 09 489. Tuners are, however, already known the gain of whose active switching elements is controlled, their operating point being altered for this purpose by a control circuit. The control takes the form, for example, of an upward adjustment of the operating-point current, thus lowering the gain, as indicated in DE-PS No. 11 76 718.